Kidney disease—known as nephropathy—is common in people with diabetes. Diabetes is the leading cause of kidney disease in Canada. Up to 50% of people with diabetes will have signs of kidney damage in their lifetime.
High blood glucose (sugar) levels and high blood pressure can damage the kidneys and prevent them from functioning properly or even cause them to fail completely. Kidney disease is a serious complication associated with diabetes.
Your kidneys
The kidneys are two bean-shaped organs located just below the ribs, near the back. Their job is to filter the blood so that waste is removed through the urine. The kidneys also regulate the amount of fluid and salt in the body and are important in controlling blood pressure.
The good news is that good diabetes management and regular kidney screening can prevent or delay the loss of kidney function.
The effects of kidney disease
Over time, high blood sugar levels can damage tiny blood vessels in your kidneys, which means they cannot filter your blood properly.
As a result, tiny particles of protein (microalbumin) spill into the urine; this is called microalbuminuria. As kidney disease progresses, larger amounts of protein spill into the urine; this condition is called proteinuria.
As kidney disease progresses, waste products start to build up in your blood because your body can't get rid of them. If left untreated, your kidneys will eventually fail (this is known as "end-stage renal failure") and dialysis or a kidney transplant will be required.
Diabetes can also affect the nerves that tell you when your bladder is full. The pressure from a full bladder can damage the kidneys. If urine remains in the bladder for a long time, it can increase your risk of developing a urinary tract infection, which can spread to the bladder.
Prevention & treatment of kidney disease
Kidney disease is closely linked to high blood sugar, high blood pressure and smoking. The best way to prevent or delay kidney damage is to:
- keep your blood sugar and blood pressure at target
- avoid smoking
- take your medications as prescribed
- have your blood cholesterol checked annually and keep it at target
- follow a healthy meal plan (if you have protein in your urine, a dietitian may recommend other changes to your diet)
- exercise regularly
- talk to your doctor about getting screened
If you've already been diagnosed with kidney damage or kidney disease, you may need to limit certain foods to prevent waste products building up in your body. Your health-care team may suggest you limit protein foods or foods high in potassium, phosphate or sodium. Controlling your blood pressure is also very important. You should see a registered dietitian for diet advice that is right for you.
In advanced or "end-stage" kidney disease, dialysis may be needed to do the job of the kidneys.
Screening tests
Most people don’t experience any symptoms in the early stages of kidney disease but there may be changes in your blood pressure and swelling in your legs and feet. It's important to get screened regularly to detect kidney problems as early as possible.
ACR urine test
The albumin/creatinine ratio (ACR) test measures the amount of protein in your urine. The more protein found in your urine, the more likely it is that kidney damage has started to occur. For people with diabetes, a result of 2.0 or higher may indicate kidney damage.
eGFR blood test
Another test used to check your kidney function is the estimated Glomerular Filtration Rate (eGFR). The eGFR is a blood test used to see how well the kidneys are working. If your GFR number is low, your kidneys are not working as well as they should. The earlier kidney disease is detected, the better the chance of slowing down its progression.
You'll likely be screened when you are first diagnosed with type 2 diabetes, 5 years after you are diagnosed with type 1 diabetes, and then once per year after that.